AWS & Cloud interview questions and quick answers

An ALB listener evaluates rules in priority order. Each rule has conditions, such as path, host header, HTTP header or query string, and an action, usually forward to a target group. A default rule catches everything else.

Aurora is AWS's cloud-built MySQL- and PostgreSQL-compatible database. It stores data in a shared cluster volume copied six ways across three AZs, supports up to 15 low-lag replicas, and fails over faster than standard RDS.

Target tracking holds a metric near a value you set, like 50% CPU. Step scaling adds or removes capacity in sized steps based on alarm thresholds. Scheduled scaling changes capacity at set times for predictable load.

An Auto Scaling group keeps the right number of healthy EC2 instances running, adding or removing them based on policies such as target CPU. A load balancer spreads incoming traffic across those instances in multiple AZs. The ASG registers new instances with the load balancer's target group and replaces any that fail health checks.

Enable MFA on the root user, do not create access keys for it, and use it only for the few tasks that need it. For daily work use IAM Identity Center or IAM users and roles with least privilege.

Lazy loading fills the cache only when a read misses, then stores the result. Write-through updates the cache at the same time as the database on every write, so reads are rarely stale but the cache holds data that may never be read.

Amazon Web Services — cloud computing platform offering compute, storage, databases, networking, and 200+ services. Pay-as-you-go pricing.

Elastic Compute Cloud — virtual servers in the cloud. Choose OS, instance type, storage. Auto-scaling for load changes.